Physical Oceanography measured with UCTD (Underway CTD) during MERIAN cruise MSM93

• Main Authors: Hofmann, Zerlina, von Appen, Wilken-Jon, Mathieu, Laura, Hagemann, Jonas, Engicht, Carina, Kuhlmey, David
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2021
• Subjects: Fram Strait; underway CTD; Event label; DATE/TIME; LATITUDE; LONGITUDE; DEPTH, water; Pressure, water; Temperature, water; Salinity; Temperature, water, potential; Density, sigma-theta 0; CTD, underway; CTD/Rosette; Drifter; Calculated; MSM93; Maria S. Merian; FRontiers in Arctic marine Monitoring FRAM; Physical Oceanography @ AWI AWI_PhyOce; Arctic
• Online Access: https://dx.doi.org/10.1594/pangaea.939712; https://doi.pangaea.de/10.1594/PANGAEA.939712

The Teledyne Underway CTD was operated in tow-yo mode: the winch brake is disengaged and the probe is in approximate free-fall at 4m/s to 1m/s vertical speed collecting data for a cast. Then the brake is engaged and the probe is hauled in until it is within 10m horizontal behind the vessel at the sea surface. The winch is then disengaged and the next cast starts. A straight section is collected with the same probe in the water. At the end of the section, the probe is recovered. The data is recorded internally on the probe and only read out once the probe is back on deck. Here we provide 1 m vertically averaged data from the downcasts. The processing follows Ullman and Hebert: “Processing of Underway CTD Data”, Journal of Atmospheric and Oceanic Technology (2014), https://doi.org/10.1175/JTECH-D-13-00200.1. A front in the open ocean region in the vicinity of the ice edge in Fram Strait was searched for with a ~100km long constant depth Triaxus transect on July 8. When a front had been found, it was surveyed in 3D by parallel UCTD sections and drifters were deployed. The front was followed until July 16 with the repeat of parallel UCTD and Triaxus sections. During one UCTD section, an operator error resulted in the fact that the probe appeared to have been started while in fact it had not been started before deployment. In total 21 sections were occupied excluding the section where no data was recorded (station MSM93_62-1).